How Much Protein Do Endurance Athletes Need?

When people think about protein, they often picture bodybuilders and strength athletes. But endurance athletes, from runners and cyclists to triathletes, also rely heavily on protein. Every long run, hard interval session, or big training week places stress on the body. Muscles are broken down, energy systems are pushed, and the body needs the right nutrients to repair, rebuild and adapt. Getting enough protein helps endurance athletes recover faster, maintain lean muscle, and support the training adaptations that ultimately improve performance.

Table Of Contents

• What Does Protein Actually Do?

• Why Do Endurance Athletes Need More Protein?

• How Does Protein Support Performance?

• What Does A Day Of Protein Look Like For A 70kg Athlete?

• Key Takeaways

What Does Protein Actually Do?

Protein provides amino acids, the building blocks the body uses to repair and rebuild tissues¹. During exercise, muscle fibres experience small amounts of damage and the body responds by repairing them stronger than before, a process known as muscle protein synthesis.

For endurance athletes, protein supports several important functions:

• Repair and rebuilding of muscle tissue after training²,³
• Formation of mitochondrial proteins, which help muscles produce energy aerobically⁴,⁵
• Production of enzymes and hormones involved in metabolism⁶
• Immune function⁷,⁸

Why Do Endurance Athletes Need More Protein?

Endurance training increases protein requirements for several reasons. During prolonged exercise, small amounts of amino acids can be used for energy, slightly increasing protein needs⁹. Repetitive movements such as running and cycling also place continual stress on muscles, creating small amounts of damage that require amino acids for repair. Protein also supports recovery from training.

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Endurance exercise stimulates the development of mitochondrial proteins and other metabolic changes that improve the muscle’s ability to produce energy efficiently⁴. Combined with long training sessions and higher whole-body protein turnover, these factors mean endurance athletes typically benefit from around 1.6-2.0g of protein per kilogram of body weight per day, with some newer research suggesting 1.8-2.0g/kg/day during heavy training⁴,¹⁰,¹¹.

How Does Protein Support Performance?

Protein doesn’t directly fuel endurance exercise like carbohydrates do, but it plays an important role in helping athletes recover and adapt to training. It helps repair muscle fibres damaged during long or intense workouts and supports recovery between sessions. Adequate protein intake also helps maintain lean muscle mass, particularly during heavy training blocks or periods of low energy availability. In simple terms, protein helps endurance athletes recover, adapt, and absorb the training they do.

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From a physiology perspective, protein supports performance by driving muscle protein synthesis, the process responsible for repairing and remodelling muscle tissue after exercise⁹. Endurance training also stimulates the synthesis of mitochondrial proteins, which improve the muscle’s ability to produce energy aerobically and support long-term metabolic adaptations⁴.

Adequate protein intake also helps regulate whole-body protein turnover, reducing excessive muscle breakdown during high training loads or periods of low energy availability. These processes collectively support recovery, adaptation, and the ability to sustain high training volumes over time.

What Does A Day Of Protein Look Like For A 70kg Athlete?

If an endurance athlete weighs 70kg, a protein target based on current research would look like 126-140g protein/day.

This might look like:

Breakfast → 200g of plain Greek yogurt + ½ cup of oats + ½ cup of berries [25g Protein]
Snack → Smoothie: 300ml of milk, 15g almonds, ¼ cup of muesli + 1 Tbsp peanut butter and 1 banana [20g Protein]
Lunch → 120g chicken, 1 cup of rice and unlimited salad [35g Protein]
Snack → 170g of cottage cheese and 3-4 wholegrain crackers [20g Protein]
Dinner → 150g salmon, 250g of potatoes and1 cup of beans and broccoli [35g Protein]

Daily Total = 135g Protein

Key Takeaways

Protein is not just important for strength athletes, it also plays a crucial role in endurance sports. Emerging research suggests endurance athletes benefit from around 1.8-2.0g/kg/day, which helps support recovery, muscle remodelling and adaptations to training. When combined with adequate carbohydrate intake, total energy and a balanced whole-food diet, this level of protein intake helps athletes recover, adapt to training and maintain performance.

Ash Miller
Dietitian and Nutritionist (Masters)
Bachelor of Physical and Health Education
Instagram: @ashthomo_nutrition

Reference:

1. Nunes, E. A., Colenso-Semple, L., McKellar, S. R., et al. (2022). Systematic review and meta-analysis of protein intake to support muscle mass and function in healthy adults. Journal of Cachexia, Sarcopenia and Muscle.
2. Morton RW et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine.
3. Cintineo HP et al. (2018). Effects of protein supplementation on performance and recovery in resistance and endurance training. Frontiers in Nutrition.
4. Moore DR et al. (2014). Protein ingestion to stimulate muscle protein synthesis. Journal of Gerontology.
5. Cintineo HP et al. (2018). Protein supplementation and exercise performance. Frontiers in Nutrition.
6. The Editors of Encyclopaedia Britannica. Role of enzymes in metabolism [Internet]. Encyclopaedia Britannica; 2026 Feb 3 [cited 2026 Mar 7]. Available from: https://www.britannica.com/science/protein/Role-of-enzymes-in-metabolism
7. Gleeson M. (2007). Immune function in sport and exercise. Journal of Applied Physiology.
8. Venkatraman JT & Pendergast DR. (2002). Effect of dietary intake on immune function in athletes. Sports Medicine.
9. Phillips, S. M., & Van Loon, L. J. C. (2011). Dietary protein for athletes: from requirements to metabolic advantage. Applied Physiology, Nutrition and Metabolism.
10. Kato H, Suzuki K, Bannai M, Moore DR. Protein requirements are elevated in endurance athletes after exercise as determined by the indicator amino acid oxidation method. Br J Nutr. 2016;116:2137–44. doi:10.1017/S0007114516004140.
11. Witard OC, Hearris M, Morgan PT. Protein nutrition for endurance athletes: a metabolic focus on promoting recovery and training adaptation. Sports Med. 2025;55(6):1361-1376. doi:10.1007/s40279-025-02203-8.

Disclaimer:

The content in this blog is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always speak with your doctor or allied health team before changing your diet, exercise, or taking supplements, especially if you have a health condition or take medication. Please use this information as a guide only. Aid Station doesn't take responsibility for individual outcomes.